Core drill



C. A. DEAN CORE DRILL Dec. 18, 1934.

Original Filed Aug. 25, 1932 Rmwm O@ N .0 m. T. MA n w Hm a ,n

Patented Dec. 184, 1934 Charles A. Dean,

Bakersfield, Calif.

Refiled ior abandoned application No.

` 630,074, August 23,1932.

26, 1933, Serial No. 673,125.

' ar'y 13, 1933 7 Claims.

This invention relates to core drills for earth boring,land moreparticularly to improvements for lretaining acore sample in drills ofthe type in which core-gripping elements are inserted and are retractedfrom a core in positive manner. by

longitudinal play between a core barrel and a portion of-'the drillstem.An illustration of rotary core drill having core grips actuatedpositively by play of a core barrel is exhibited in Dean Patent1,850,386. The present invention is applicable broadly to forms of coredrill in which longitudinal or vertical play between a drill sub andcore barrel alternately projects and retracts core-gripping dogs.

In abstracting a core, the weight of the core barrel with itscontentshas been utilized to keep the core barrel suspended in itslowermost position from-the drill sub so that the core-gripping elementswill be forced most effectively into the earth sample. However in actualoperation varisus conditions intervene to cause the core dogs to bewithdrawn sufliciently to score the core sample iriuriously. or untiltheir weakened Agrip permits f .e core to` slide down and be spoiled orbe lost entirely. This frequently occurs deep in the earth whereconditions are unknown or are difcult to anticil` e, and are practicallyimpossible to alter. Such inadvertent release of the gripping elementsresults often from the practice of drillers to whip the drill up anddown during preparation and withdrawal of the core sample.

An object of this invention is to assure positive gripping by thecore-retaining elements during the entire operation of abstracting acore that has been obtained in the drill. A general object of thisinvention is to keep the core-gripping elements projected firmly intothe core once actual withdrawal of the core barrel in the drill hole hasbeen started. It is an object to overcome scoring or inadvertent releaseof a core even though, for example, the drill lbe dropped or be restedon some obstruction in the drill hole; yet another object is to providepositive core-locking means that will not interfere with repeatedraising and lowering of the drill during actual core cutting. It is anobject to provide core locking means that will secure the core-grippingdogs effectively in various positions or degrees of penetration of thecore.

A further object of this invention is to provide a core lockingstructure that is applicable tordiffering drills of the general ltypedescribed;v one that does not interfere with normal passage of slushingfluid through the drill, and is positive in action but simple instructure. Another object This application May In Canada Febru- (Cl.Z55-72) is 4to provide core locking means that, while economical tomanufacture andto maintain under eld conditions, will permit the use ofa variety of actual locking elements. Other objects will appear with thefollowing description of illustrative 5 lembodiments of this invention,as 'shown in the accompanying drawing.

`Referring to the drawing,

Fig.' 1 shows in vertical section a core drill embodying one form ofthis invention; and

Fig. 2 shows in vertical section a modified locking structure embodyingthis invention; and

Fig. 3 shows in horizontal section along the plane III-III of Fig. 1 aparticular form of mounting of core dogs and core container for l5 usewith this invention.

Figs. 4, 5, and 6 illustrate particular modications of thiscore-container locking means combiriation.A

Referring more particularly to the drawing, Fig. 1 illustrates a coredrill comprising a drill stem lv having a central bore 2.; The stem isconnected to a drill sub that comprises an outer core barrel 3 andreamer blades 4. An inner core barrel 5 is mounted with splinedconnection for 2 5 longitudinal play within the outer barrel. Core dogs6 are seated between the inner and outer barrels so as to be projectedinto a core when the inner barrel moves down within the outer barrel,and to be withdrawn from the core by rela- 30 tive zupward movement ofthe inner barrel, as

' when the drill rests on the bottom of the drill hole. Between theinner and outer barrels is space communicating with the bore oi' thedrill stem for ilow of the flushing iluid usually supplied to thecutters. Y

-As shown, the bore of the drill' stem terminates in an enlarged cavityabove the inner core barrel. 'lhe upper walls of the cavity expanddownwardly by successive stepped enlargements I of the bore 40 or thedrill stem. The top portion 8 of the inner core barre'. is somewhatconcave. Thus structure is provided for retaining 4or wedging a spacingelement, as bar 9, to minimize play or telescoping between the innercore barrel and the drill stem. Before'a core is.elevated, lockingelement or bar 9 is dropped through the drill stem, usually along withheavy slushing fluid, until that element rests on top of the inner corebarrel and against the shoulders 'I at the bottom of the drill stembor/e; 50 In this way', during elevation of a core, the inner barrel isheld in some relatively lower ,y tion to prevent the core dogs 6 frombeing irom the core even though the drill be dropped against anobstruction. Further, this structure permits the dogs to work moredeeply into a core.

Modications are contemplated in this form of the invention. For example,as illustrated in Figs. 4 and 5, the upper cavity walls may be roughenedor grooved instead of containing the distinct shoulders 7. Similarly thetop of the inner core barrel may be modified. Also the single bar may bemultiplied as in Fig. 4 element 20, or extended even to form a. more orless conical locking member as in Fig. 5-element 21.

An alternative embodiment of this invention is illustrated in Fig. 2, inthat a spheroidal locking element 10 is engageable in the cavity betweenthe drill stem and the inner core barrel. The upper Walls of the cavitymay flare simply, as shown, or may comprise pronounced shoulders. AlsoFig. 2 illustrates a modification of the top portion of the inner corebarrel, having shoulder 11 and having a contracted top 12 that is spacedfrom the walls of the outer barrel sufhciently to permit a ball 10 topass down to shoulder 11. Thus the ball may wedge to provide lockingengagement against any tendency of the inner barrel to rise within thestem. In this way the coregripping elements are held in a core. With thetop of the inner core barrel modified as shown, it is contemplated thatan elongate locking member may be used, such as a wedge-shaped bar orchunk as in Fig. 6 element 22. l

The locking structure of this invention is exceedingly simple, so as topromote satisfactory core sampling even under the requirements ofpractical operations in varied formations and in out-of-the-Waylocalities. AMoreover, when the core is to be Withdrawn there isprovided positive locking of the core-gripping elements. Neverthelessthere is no interference with continued flow of slushing uid.

This invention has been illustrated with reference to a particular,simple form of core drill. However other forms of core drill areavailable in common use. Nevertheless the principles of this inventionare applicable to provide a simple structure for preventing play of acore barrel within an outer barrel during abstraction of the core or forpreventing withdrawal of core-retaining elements on dropping of the corecontainer during abstraction or during severing of the core.

In accordance with the patent statutes, illustrative embodiments andpreferred operation of this invention have been described, but theinvention is not limited thereto, Within the appended claims except aslimited by the prior art.

This present application comprises the subjectmatter of my formerapplication Ser. No. 630,074.

What is claimed is:

1. A core drill comprising a tubular drill stem and a depending drillsub, a core container mounted for longitudinal play within the sub,core-gripping elements mounted to be engaged by the drill sub forpenetration into a core and retraction therefrom respectively on raisingand lowering of the drill sub relatively to the core container, andmeans within the drill to lock the core-gripping elements againstretraction at different relative positions 'of drill sub and container.

2. A core drill comprising a tubular drill stem and depending drill sub,a core container ,mounted for longitudinal play within the sub andterminating .in a core cutter projecting below the sub, core-grippingelements mounted for engagement by the sub to be'retracted on relativeupward-movement of the container, va cavity between the drill stem andthe core container, and means operative within the cavity atsubstantially any relatively lower position of the core container tolimit said longitudinal play and lock I the core-gripping elementsagainst retraction.

3. A core drill comprising a drill stem having a central bore, a drillsub depending therefrom, a tubular core container mounted forlongitudinal movement relatively to the sub, and coreretaining elementsmounted for insertion and retraction by said relative movement, theupper portion of the core container and the walls of the r drillstemabove the core container being adapted to grip a relatively largeobject receivable through the drill stem to limit said relative movementand lock the core-retaining elements against retraction.

4. A core drill comprising a drill stem having a central bore, a tubulardrill sub, a corecontainer mounted for vertical play Within the sub andterminating in a core cutter projecting below the sub, and core-grippingelements mounted for engagement by the sub to be retracted on relativeupward movement of the container, the bore of the drill stem beingenlarged above the core z container to receive a wedging element and,'with the upper portion of the core container, conforming to wedge saidelement against the drill stem for preventing play of the container andretraction of the core-gripping elements.

5. A core drill comprising a drill stem having a central bore, a tubulardrill sub, a core container mounted for vertical play in the sub, andcore-retaining elements mounted for insertion and retraction by saidplay, the walls of the drill stern bore receding in a step conformationto form a space above the core container, and the top of the corecontainerbeing adapted to wedge an elongate object against the' steppedwalls to limit play and lock the core-retaining elements againstretraction.

6. A core drill comprising a drill stem having a central bore, a tubulardrill sub, a core container mounted for Vertical play in the sub, andcoreretain'ing elements mounted for insertion and retraction by saidvplay, the walls of the drill stem bore being enlarged downwardly to forma space above the core container, and the top portion of the corecontainer being concave inwardly to wedge a relatively large object inlthe space for limiting play and locking the core-retaining elementsagainst retraction.

'7. A core drill comprising a tubular drill stem, a drill sub having acore container mounted for vertical play therein, and core-grippingelements adapted to be inserted andsretracted by the drill sub in saidplay, the top portion of the core container and the walls of the drillbore together forming a cavity adapted to receivea wedging object fromthe drill stem, with walls to retain the object for wedging thecontainer downwardly in the drill stem to lock the core-grippingelements against retraction.

CHARLES A. DEAN.

